In a large mixing bowl, whisk together all-purpose flour, baking powder, ground cinnamon, ground nutmeg, salt, and granulated sugar. Set aside.

In a separate bowl, whisk the egg with milk, melted unsalted butter, and vanilla extract until smooth.

Pour the wet mixture into the dry ingredients and gently fold them together, ensuring not to overmix.

Fold in the diced apple evenly into the batter.

Let the batter rest for 5-10 minutes.

Heat a griddle or non-stick skillet over medium heat and lightly oil the surface.

Pour ¼ cup of batter onto the hot surface for each pancake.

Cook for 2-3 minutes, until bubbles form, then flip and cook for another 2-3 minutes until golden brown.

Keep pancakes warm in a preheated oven at 200°F if needed.